Safe and vault protector.



. E. MENNE. SAFE AND V AULT PROTECTOR. APPLICATION FILED Nov. en 1909.

948,929. Patented Feb. 8, 1910.

l Eras ferm@ l moz/news ERNST MENNE, OF CREUZTI-IAL, GERMANY.

SAFE .AND VAULT PROTECTOR.

Specification of Letters Patent.

Patented ret. s, loro.'

Application led November 8, 1909. Serial No. 526,914.

To all whom it may concern:

Be it known that I, ERNST MENNE, chemist, a subject of the GermanEmperor, and resident of Oreuzthal, Westphalia, Germany, have invented anew and useful Safe and Vault Protector, of which the following is aspecification.

My invention relates to an improvement in safe and vault protectors andis designed to provide a simple means whereby an electric alarm will begiven if heat is applied to the outside of the safe or vault for thepurpose of breaking thereinto.

Since the invention of the Oxy-acetylene burners and of the electric arcblast device, it has been found comparatively easy for a burglar topenetrate the wall of a safe or 'door of a vault, no matter howcarefully made.

The object of the present invention is to produce a construction wherebywhen such an attempt is made, an alarm will be given.

In the accompanying drawing-Figure l represents an ordinary safe, partlybroken away, showing an alarm bell and circuit and showing a burglarattempting to fuse a portion of the frontof the safe. Fig. 2 is a crosssection on a larger scale of a portion of the wall of the same.

1 represents a safe of ordinary shape. This safe is provided with alining 2 of thermo-electric elements, forming a thermopile, which isconnected to wires 3, leading to a signal device 4. The thermo-electricpile is made of long, thin strips with which the inner wall of the safeand safe door can be lined crosswise, so as to form a net-like coating,as shown in the drawing, this coating being preferably protected by acovering plate on the inside. VThus the whole device occupies only avery small space and 1s always in working order. It also affords thelargest factor of safety, inasmuch as the attempt to fuse even a smallhole will aect at least one thermo-element, thereby producing anelectric current, which actuates the alarm. One advantage of this formof device is that the heat conduction of the walls of the safe, if anOxy-acetylene burner, for instance, is skilfully handled by a burglar,is only very small, only a little heat being conducted from the cuttingline proper to the surrounding parts. This, however, does not render myconstruction inoperative, because the entire interior of the safe islined crosswise with a net-like coating.

The thermo-elements are of any desired type, but they are so arrangedthat the soldered connection il is closer to the outer wall of the safethan the remaining portion of the strips.

In actual use, the wires 3 are concealed or so located as not to beeasily found, and, if desired, alarm devices may be located within thesafe itself, so that they will be set off when the burglar commences hiswork, thereby frightening him away.

The construction shown is applicable not only 'to safes, but to vaultdoors and similar constructions.

A safe provided with a net-like interior coating, composed ofthermo-elements forming a thermo-pile, and an alarm device connectedthereto, substantially as described.

In testimony, that I claim t-he foregoing as my invention, I have signedmy name in presence of two witnesses, October 1909.

ERNST MENNE.

Witnesses:

Louis HAMBORG, OSCAR DEPNER.

